There is a reactor as one of parts of a circuit for operations of stepping-up and stepping-down a voltage. In a typical form of a reactor employed, for example, in a converter that is loaded on a vehicle such as a hybrid car, a pair of coils, each formed by winding a wire, are disposed side by side around respective parts of a magnetic core having a annular shape, e.g., an O-like shape.
Patent Literature (PTL) 1 discloses a rector including one coil and the so-called pot type core, i.e., a magnetic core having an E-E shaped cross-section, the core including an inner core disposed inside the coil and an outer core disposed to cover substantially an entire outer periphery of the coil. The pot type core has a small size and is suitable as a component loaded on a vehicle where an installation space is small. Particularly, the reactor disclosed in PTL 1 can be produced in a smaller size by setting a saturation magnetic flux density of the inner core to be higher than that of the outer core, thus reducing a cross-sectional area of the inner core, by setting magnetic permeability of the outer core to be lower than that of the inner core, thus dispensing with a gap member, or by designing a structural form not using a case. Further, PTL 1 discloses, as a constituent material of the outer core, a mixture of magnetic powder and resin (hereinafter referred to as a “magnetic mixture”).